UNAUTH UNCOORD PENETRATION OF AIRSPACE.

Narrative

ZLC CLRED US FOR THE NDB/DME A APCH TO SUN. WHEN WE HAD THE ARPT IN SIGHT; WE ATTEMPTED TO CONTACT ZLC. THEY RESPONDED WHEN WE WERE 2 MI ON FINAL. AT THAT TIME THEY TOLD US TO CONTACT THE TWR. WHEN WE CONTACTED THE TWR THEY CLRED US TO LAND. AFTER LNDG THEY TOLD US TO CALL THE TWR AS WE HAD ENTERED THE ATA WITHOUT A CLRNC. AFTER TALKING WITH THE TWR WE FOUND OUT THAT ZLC HAD TOLD THEM WE WERE VFR WHEN WE WERE IFR. WE NEVER CANCELLED IFR UNTIL LNDG. THE TWR SAID WE WERE WITHIN 1.5 MI OF AN SMA ON 1/2 MI BASE. ALL WE SAW WAS AN ACFT CLRING THE RWY WHEN WE WERE ON A 2 MI FINAL. THE TWR NEVER SPOKE TO ANY ACFT ON THE RADIO WHILE WE WERE ON IT. THE TWR AND CTR NEED TO WORK WITH EACH OTHER AND COMMUNICATE WITH EACH OTHER. THE TWR INDICATED TO US THAT ZLC DIDN'T KNOW WHAT THEY WERE DOING. WHILE ON AN IFR FLT PLAN AND APCH IT IS ATC'S RESPONSIBILITY TO CLR US IN ALL CTLED AIRSPACE; ATA'S; ETC. WE WERE CLRED FOR THE APCH AND 2 MI OUT THE TWR CLRED US TO LAND. ZLC AND SUN TWR NEED TO WORK TOGETHER SO A MAJOR ACCIDENT DOESN'T OCCUR.